<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>

</head>
<body>

<div id="a">随机变颜色</div>
<div id="b">变宽</div>
<div id="c">随机变颜色+变宽</div>


<style>
    div{
        width: 200px;
        height: 100px;
        margin-top: 10px;
        line-height: 100px;
        font-size: 20px;
        color: white;
        text-align: center;
    }
    #a{
        background: orangered;
    }
    #b{
        background: dodgerblue;
    }
    #c{
        background: limegreen;
    }
</style>


<script src="index.js" type="module"></script>

</body>
</html>